Biology subjects

Tarangelo, A.

Publications and source records attributed to Tarangelo, A..

3 recordsLinked to original sources

bioRxiv2023

A Cell Cycle-Dependent Ferroptosis Sensitivity Switch Governed by EMP2

Ferroptosis is a non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation. Ferroptosis can be induced by system xc- cystine/glutamate antiporter inhibition or by direct inhibition of the phospholipid hydroperoxidase glutathione peroxidase 4 (GPX4). The regulation of ferroptosis in response to system xc- inhibition versus direct GPX4 inhibition may be distinct. Here, we show that cell cycle arrest enhances sensitivity to ferroptosis triggered by GPX4 inhibition but not system xc- inhibition. Arrested cells have increased levels of oxidizable polyunsaturated fatty acid-containing phospholipids, which drives sensitivity to GPX4 inhibition. Epithelial membrane protein 2 (EMP2) expression is reduced upon cell cycle arrest and is sufficient to enhance ferroptosis in response to direct GPX4 inhibition. An orally bioavailable GPX4 inhibitor increased markers of ferroptotic lipid peroxidation in vivo in combination with a cell cycle arresting agent. Thus, responses to different ferroptosis-inducing stimuli can be regulated by cell cycle state.

cancer biology↗

bioRxiv2022

In-vivo characterization of glutamine metabolism identifies therapeutic targets in clear cell renal cell carcinoma

Targeting metabolic vulnerabilities has been proposed as a therapeutic strategy in renal cell carcinoma (RCC). Here, we analyzed metabolism in patient-derived xenografts (tumorgrafts) from diverse forms of RCC. Tumorgrafts from VHL-mutant clear cell RCC (ccRCC) retained metabolic features of human ccRCC and engage in oxidative and reductive glutamine metabolism. We used several approaches to suppress glutamine metabolism and test the effect on tumor growth. Genetic silencing of isocitrate dehydrogenase-1 or -2 impaired reductive labeling of TCA cycle intermediates and suppressed tumor growth. Glutaminase inhibition resulted in modest growth suppression and variable effects on glutamine metabolism in vivo. Infusions with [amide-15N]glutamine revealed persistent amidotransferase activity during glutaminase inhibition, and blocking these activities with the amidotransferase inhibitor JHU-083 also reduced tumor growth. We conclude that ccRCC tumorgrafts catabolize glutamine via multiple pathways, perhaps explaining why it has been challenging to achieve therapeutic responses in patients by inhibiting glutaminase. TeaserGlutamine fuels the TCA cycle and amidotransferase pathways in clear cell renal cell carcinoma.

cancer biology↗

bioRxiv2021

Nucleotide Biosynthesis Links Glutathione Metabolism to Ferroptosis Sensitivity

Nucleotide synthesis is a metabolically demanding process essential for cell division. Several anti-cancer drugs that inhibit nucleotide metabolism induce apoptosis. How inhibition of nucleotide metabolism impacts non-apoptotic cell death is less clear. Here, we report that inhibition of nucleotide metabolism by the p53 pathway is sufficient to suppress the non-apoptotic cell death process of ferroptosis. Mechanistically, stabilization of wild-type p53 and induction of the p53 target gene CDKN1A (p21) leads to decreased expression of the ribonucleotide reductase (RNR) subunits RRM1 and RRM2. RNR is the rate-limiting enzyme of de novo nucleotide synthesis that reduces ribonucleotides to deoxyribonucleotides in a glutathione-dependent manner. Direct inhibition of RNR conserves glutathione which can then be used to limit the accumulation of toxic lipid peroxides, preventing the onset of ferroptosis. These results support a mechanism linking p53-dependent regulation of nucleotide metabolism to non-apoptotic cell death.

cancer biology↗